Field of the Invention
The present invention relates to a thermocompression bonding structure and a thermocompression bonding method in which two members are pressurized and heated to be bonded to each other by use of metal fine particles.
Description of the Background Art
For this kind of thermocompression bonding technique, for example, a technique described in JP-A-2011-249562 has been proposed. According to the thermocompression bonding technique, electrode terminals of substrates to be stacked are bonded with each other as follows. That is, a transistor and multilayer wiring are formed on a substrate, and an insulating film is formed to cover the multilayer wiring. An opening portion is formed to expose the wiring in the insulating film, and an organic solvent including conductive fine particles is applied to the interior of the opening portion. After first heat treatment is performed to eliminate the solvent and an organic component, the conductive fine particles are eliminated from an outer part of the opening portion by a CMP method so that an electrode terminal formed from the conductive fine particles is formed inside the opening portion. A through electrode formed in a second substrate is pressed and pushed against the electrode terminal. Second heat treatment higher in temperature than the first heat treatment is performed to partially melt the conductive fine particles to thereby bond the through electrode to the opening portion.
According to the aforementioned thermocompression bonding method described in JP-A-2011-249562, an electrode inserted into a bonding recess formed on the substrate side is heated while being pressurized in the insertion direction of the electrode so that thermocompression bonding can be attained between the electrode and the bonding recess. In this case, the pressurizing direction of the electrode inserted inside the bonding recess coincides with the insertion direction of the electrode so that the pressurizing force acts on a bonding surface between the bottom of the bonding recess and the bottom of the electrode. Accordingly, the pressure bonding in the bonding surface can be performed excellently. However, the pressurizing force does not act on a side bonding surface between a side wall of the bonding recess and an outer circumferential surface of the electrode. Thus, there still remains an unsolved problem that thermocompression bonding cannot be achieved in the side bonding surface.